Compressor stator assembly and method of installing

ABSTRACT

A compressor stator assembly includes a stator casing having a plurality of stator casing slots and a set of stator portions insertable into the stator casing slots. The stator casing and the set of stator portions are configured such that the set of stator portions only assembles to the stator casing in a single stage of the stator casing, or in a single configuration. The set of stator portions includes a plurality of stator vanes, and the stator vanes have a stator vane characteristic that varies for each stage in the stator casing. The stator vane characteristic is at least one of, a radial height of a forward sidewall, a radial height of an aft sidewall or an axial length.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S.application Ser. No. 13/556,296, filed Jul. 24, 2012, currently pending.

BACKGROUND OF THE INVENTION

The present invention relates generally to turbomachinery, and moreparticularly relates to a compressor stator assembly and a method ofinstalling the assembly.

A conventional gas turbine generally operates on the principle ofcompressing air within a compressor, and then delivering the compressedair to a combustion chamber where fuel is added to the air and ignited.Afterwards, the resulting combustion mixture is delivered to the turbinesection of the engine, where a portion of the energy generated by thecombustion process is extracted by a turbine to drive the compressor viaa shaft.

In multi-stage compressor sections, stators vanes are placed at theentrance and exit of the compressor section, as well as between eachcompressor stage, for purposes of properly directing the airflow to eachsuccessive compressor stage. As a result, stator vanes are able toenhance engine performance by appropriately influencing air flow andpressure within the compressor section.

Each stator stage generally consists of an annular array of airfoils, orvanes. A stator stage is typically formed in segments as stator vaneunits consisting of one or more airfoils supported by the base. Thesestator vane units are then individually mounted to the compressor casingto form an annular array, so that the airfoils project radially betweenan adjacent pair of rotor stages.

Stator vanes in an industrial gas turbine compressor are loaded andunloaded during start-stop cycles. In addition, the vanes are subject tosmall pressure fluctuations during operation. These result in relativemotion between the vane base and the casing in which the vanes areassembled. The relative motion results in wear of both the vane base andcasing, which, in turn, results in loose vanes. The loose vanes becomemore susceptible to relative motion and begin to chatter. Repair orreplacement of the vanes may be required. Similar problems exist betweenstator ring segments, which hold a plurality of stator vanes, the statorring segments being mounted in slots of the compressor casing.

FIG. 1 illustrates a known compressor section or compressor statorassembly 10 showing a portion of an open casing 15 of a compressorshowing five exemplary stages (rows) 20 a-20 e of stator vanes 25. Inthe embodiment shown, the casing section 15 is semicircular. The casing15 has a mounting surface 30 that may be secured to a correspondingmounting surface on another casing section with fasteners extendingthrough a plurality of holes 35. For a complete compressor, two of thesemicircular casing sections would be fitted together around a rotor(not shown).

Each stator vane 25 has an airfoil 40 that extends upwards from a base45 and radially inward towards the shaft of the compressor rotor (notshown). The airfoil 40, and stator vanes 25, are interposed between therotor blades (not shown). Certain stator stages of a compressor maymount stator vanes directly in a slot in the casing. Other stator stagesmount stator vanes in ring segments, which are then mounted in slots ofthe casing.

FIG. 2 illustrates individual stator vanes 25. Airfoil 40 extendsvertically from a base or platform 45. The base 45 has two opposingretaining faces 50. The base 45 has a pair of projections 55, one oneach of the retaining faces. The projections 55 are to be received by acorrespondingly shaped groove in a slot of the casing. The groovesretain the stator vane 25 in place in the slot of the casing. The othertwo opposing faces of the base 45 are the engaging faces 60. Theengaging faces 60 of base 45 butt against the bases 45 of adjacentstator vane units when the units are installed in a casing slot. Theretaining faces 50 and projections 55 are the same shape and size onboth sides of the stator vane 25. In this arrangement, the stator vanes25 can be rotated 180 degrees and inserted within a casing slot (or ringsegment).

FIG. 3 illustrates an enlarged side view of the casing showing a stagein which individual stator vanes are assembled in a slot of thecompressor casing. For this type of installation, a plurality of thestator vanes 25 are assembled in the casing to form the stator vanestage. The casing 15 has a plurality of slots 70 for receiving thestator vane units 25. The slot 70 has a pair of side edges 75, whicheach has a groove or dovetail-shaped recess 80. The square base dovetail80 holds the vanes 25 in place. The side edges 75 and dovetails 80 aremirror images of each other on each side of the slot. As mentionedpreviously, this allows the stator vanes 25 to be rotated 180 degreesand inserted within a casing slot (or ring segment), with the potentialfor inserting a stator vane backwards. The term “backwards” is definedas the airfoil being oriented 180 degrees from a desired orientation.Each vane unit 25 is allowed to slide into place with the base 45received in the slot 70 and the projections 55 received in thegrooves/dovetails 80. The casing 15 in the particular example shown hasan air extraction cavity 85 that underlies the stage and is formed bythe slot 70 and the stator vanes 25.

The stator vanes 25 for an individual stage are sequentially placed inthe slot 70 of the casing 15 until the full circumferential run of theslot has been filled with a designated number of stator vanes. Otherstages of stator vanes may be attached to the casing using ring segmentassemblies. The ring segment assembly includes a ring segment and one ormore stator vanes. Ring segments typically hold a plurality of statorvanes. After the ring segments have been loaded with stator vanes, thering segments are slid into circumferential slots in theturbine/compressor casing and are butted against each other tosequentially fill the circumferential slots. Blades that are larger andhave more forces placed on them may be assembled using this vane andring segment assembly to provide a stiffer base mount.

FIG. 4 illustrates a ring segment assembly 400 that is slid out and awayfrom the casing 15. The ring segment 90 receives a plurality of statorvanes 25. A base 45 of the stator vane 25 slides (in a generally axialdirection with respect to the compressor) into the ring segment 90. Thebase 45 of the stator vane 25 includes a dovetail 95 fitting into andbeing retained by a corresponding dovetail-shaped slot 100 in the ringsegment 90.

The ring segment 90 slides into the circumferential slot 70 of thecasing 15. The sidewalls 105 of the ring segment 90 are supportedaxially by the sidewalls 110 of the slot 70 when the ring segment 90 iswithin the slot 70. The square base dovetail 115 of the ring segment 90fits into the grooves 120 of the circumferential slot 70, therebyretaining the ring segments 90 in the circumferential slot 70. Ringsegments 90 are sequentially placed in the slot 70 of casing 15 untilthe slot 70 is filled with the desired number of ring segmentassemblies.

During initial assembly of turbomachine components, or subsequent repairand replacement of turbomachine components, a large number of componentsmust be installed in specific locations of the turbomachine. Forexample, a stage one stator vane must be installed in the correctposition in a stage one stator slot. A typical turbomachine may havemany stages with many corresponding components, so a high probabilityexists that a component for a specific stage may get installed in anincorrect stage (e.g., a stage five stator vane might get installed in astage six stator slot). The negative implications of this event lead tomachine malfunction or inefficiency and increase outage or constructiontime due to the need to remove and correctly install the specificcomponents.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of the present invention, a compressor statorassembly includes a stator casing having a plurality of stator casingslots and a set of stator portions insertable into the stator casingslots. The stator casing and the set of stator portions are configuredsuch that the set of stator portions only assembles to the stator casingin a single stage of the stator casing, or in a single configuration.The set of stator portions includes a plurality of stator vanes, and thestator vanes have a stator vane characteristic that varies for eachstage in the stator casing. The stator vane characteristic is at leastone of, a radial height of a forward sidewall, a radial height of an aftsidewall or an axial length.

According to another aspect of the present invention, a compressorstator assembly has an upper half and a lower half. The upper half hasone or more upper half locker segments and a plurality of upper halfpack segments. The plurality of upper half pack segments are locatedcircumferentially between the one or more upper half locker segments.The lower half has one or more lower half locker segments and aplurality of lower half pack segments. The plurality of lower half packsegments are located circumferentially between the one or more lowerhalf locker segments. At least one characteristic of the upper half isdifferent than at least one characteristic of the lower half. The atleast one characteristic of both the upper half and the lower half arechosen from at least one of, a number of pack segments, a pack segmentspan angle, and a pack segment arc length. Each of the upper half andthe lower half have a stator casing having a plurality of stator casingslots. A set of stator portions are insertable in the stator casingslots, and the stator casing and the set of stator portions areconfigured such that the set of stator portions only assembles to thestator casing in a single stage of the stator casing, or in a singleconfiguration.

According to yet another aspect of the present invention, a method ofinsuring proper installation of stator portions in a compressor statorassembly includes a step of inserting a set of stator portions into astator casing slot of a stator casing. The stator portions areconfigured such that each of the stator portions only assembles to thecompressor stator assembly in a single configuration or in a singlestage of the stator casing. The inserting a set of stator portions stepalso includes inserting a plurality of stator vanes into a ring segment.The stator vanes have a stator vane characteristic that varies for eachstage in the stator casing, and the stator vane characteristic is atleast one of, a radial height of a forward sidewall, a radial height ofan aft sidewall or an axial length. The inserting a set of statorportions step also includes inserting a plurality of ring segments intothe stator casing slot. The ring segments have a ring segmentcharacteristic that varies for each stage of the stator casing, and thering segment characteristic is at least one of, a radial height of aforward ring segment surface, a radial height of an aft ring segmentsurface, a radial height of a forward ring segment projection, a radialheight of an aft ring segment projection or a ring segment axial length.The stator casing slots have a casing slot characteristic that variesfor each stage in the stator casing, and the casing slot characteristicis at least one of, a radial height of a forward casing slot sidewall, aradial height of an aft casing slot sidewall, a radial height of aforward casing slot groove, a radial height of an aft casing slot grooveor a casing slot axial length. The stator vane characteristic and thering segment characteristic are chosen so that stator vanes and the ringsegments have asymmetrical profiles from an axial orradial/circumferential perspective. The asymmetrical profiles only allowthe stator vanes and the ring segments to be assembled in a singledirection.

These and other features and improvements of the present inventionshould become apparent to one of ordinary skill in the art upon reviewof the following detailed description when taken in conjunction with theseveral drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a compressor section including a portion of an opencompressor casing showing five exemplary stages of stator vanes;

FIG. 2 illustrates individual stator vanes;

FIG. 3 illustrates a stator vane assembled in a slot of a turbinecasing;

FIG. 4 illustrates a ring segment assembly slid out from the turbinecasing slot;

FIG. 5 illustrates an axial compressor flow path, according to an aspectof the invention;

FIG. 6 illustrates a partial, cross-sectional view of a stator casing,according to an aspect of the invention;

FIG. 7 illustrates a perspective view of a plurality of stator vanesinserted in a ring segment, according to an aspect of the invention;

FIG. 8 illustrates a cross-sectional view of a stator vane, according toan aspect of the invention;

FIG. 9 illustrates a schematic representation of a stator or compressorstator assembly, according to an aspect of the invention; and

FIG. 10 is a flowchart of a method for insuring proper installation ofstator portions in a compressor stator assembly, according to an aspectof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

One or more specific aspects/embodiments of the present invention willbe described below. In an effort to provide a concise description ofthese aspects/embodiments, all features of an actual implementation maynot be described in the specification. It should be appreciated that inthe development of any such actual implementation, as in any engineeringor design project, numerous implementation-specific decisions must bemade to achieve the developers' specific goals, such as compliance withmachine-related, system-related and business-related constraints, whichmay vary from one implementation to another. Moreover, it should beappreciated that such a development effort might be complex and timeconsuming, but would nevertheless be a routine undertaking of design,fabrication, and manufacture for those of ordinary skill having thebenefit of this disclosure.

When introducing elements of various embodiments of the presentinvention, the articles “a,” “an,” and “the” are intended to mean thatthere are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements. Anyexamples of operating parameters and/or environmental conditions are notexclusive of other parameters/conditions of the disclosed embodiments.Additionally, it should be understood that references to “one aspect” or“an aspect” of the present invention are not intended to be interpretedas excluding the existence of additional embodiments or aspects thatalso incorporate the recited features. A turbomachine is defined as amachine that transfers energy between a rotor and a fluid or vice-versa,including but not limited to gas turbines, steam turbines andcompressors.

Referring now to the drawings, FIG. 5 illustrates an axial compressorflow path 500 of a compressor 501 that includes a plurality ofcompressor stages. The compressor 501 may be used in conjunction with,or as part of, a gas turbine. As one non-limiting example only, thecompressor flow path 500 may comprise about eighteen rotor/statorstages. However, the exact number of rotor and stator stages is a choiceof engineering design, and may be more or less than the illustratedeighteen stages. It is to be understood that any number of rotor andstator stages can be provided in the compressor, as embodied by theinvention. The eighteen stages are merely exemplary of oneturbine/compressor design, and are not intended to limit the inventionin any manner.

The compressor rotor blades 502 impart kinetic energy to the airflow andtherefore bring about a desired pressure rise. Directly following therotor blades 502 is a stage of stator vanes 504. However, in somedesigns the stator vanes 504 may precede the rotor blades 502. Both therotor blades 502 and stator vanes 504 turn the airflow, slow the airflowvelocity (in the respective airfoil frame of reference), and yield arise in the static pressure of the airflow. Typically, multiple rows ofrotor/stator stages are arranged in axial flow compressors to achieve adesired discharge to inlet pressure ratio. Each rotor blade and statorvane includes an airfoil, and these airfoils can be secured to rotorwheels or a stator case by an appropriate attachment configuration,often known as a “root,” “base” or “dovetail”. In addition, compressorsmay also include inlet guide vanes (IGVs) 506, variable stator vanes(VSVs) 508 and exit or exhaust guide vanes (EGVs) 510. All of theseblades and vanes have airfoils that act on the medium (e.g., air)passing through the compressor flow path 500.

Exemplary stages of the compressor 501 are illustrated in FIG. 5. Onestage of the compressor 501 comprises a plurality of circumferentiallyspaced rotor blades 502 mounted on a rotor wheel 512 and a plurality ofcircumferentially spaced stator vanes 504 attached to a staticcompressor case 514. Each of the rotor wheels 512 may be attached to anaft drive shaft 516, which may be connected to the turbine section ofthe engine. The rotor blades and stator vanes lie in the flow path 500of the compressor 501. The direction of airflow through the compressorflow path 500, as embodied by the invention, is indicated by the arrow518 (FIG. 5), and flows generally from left to right in theillustration.

The rotor blades 502 and stator vanes 504 herein of the compressor 501are merely exemplary of the stages of the compressor 502 within thescope of the invention. In addition, each inlet guide vane 506, rotorblade 502, stator vane 504, variable stator vane 508 and exit guide vane510 may be considered an article of manufacture. Further, the article ofmanufacture may comprise a stator vane and/or a stator casing and/or aring segment configured for use with a compressor.

Aspects of the present invention provide a collection of strategicallydefined geometric features incorporated in the compressor statorassembly and on the stator vanes, ring segments (also referred to asstator vane attachments), and casing slots for a unique configuration ofthe compressor stator assembly. This unique (or single) configurationprevents mis-assembly due to assembly errors. Assembly errors occur whena stator vane or ring segment is installed in the wrong stage or thewrong half of the casing. For example, a stator vane or ring segment maybe designed for an upper half of the compressor, but assembly errorleads to installation in the lower half of the compressor. Further, thisunique configuration provides a physical method of mis-assembly proofingwhere the wrong method of installation may not be visually apparent. Forexample, it would be difficult to place a stage five stator vane in astage thirteen stator slot, however, it would be very easy tointerchange (and install incorrectly) a stage eleven stator vane with astage twelve stator vane. Adjacent stages may have very similarly sizedcomponents, and even though these sizes may look visually the same, theimproper installation of components can lead to severe machine damageand loss of efficiency.

FIG. 6 illustrates a partial, cross sectional view of a stator casing600 that has a plurality of stator casing slots 604, according to anaspect of the present invention. In this example, a ring segment 700,shown in phantom, is positioned within the stator casing slot 604. Thestator casing slot has an axial length 605 which may be the distancebetween the forward sidewall 606 and the aft sidewall 607.Alternatively, the axial length 610 may be measured from the forwardsurface and aft surface of the forward groove 612 and aft groove 613.The stator casing slot 604 also has two radial heights. The radialheight 620 of the forward sidewall 606 may be measured from the bottomof slot 604 to the top of forward sidewall 606. The radial height 630 ofthe aft sidewall 607 may be measured from the bottom of slot 604 to thetop of aft sidewall 607. According to an aspect of the presentinvention, the stator casing slots 604 may have one or more casing slotcharacteristics that vary for each stage in the stator casing 600. Thecasing slot characteristics include a radial height 620 of a forwardcasing slot sidewall 606, a radial height 630 of an aft casing slotsidewall 607, a radial height 614 of a forward casing slot groove 612, aradial height 615 of an aft casing slot groove 613 or a casing slotaxial length 605, 610. The forward radial height 620 may be configuredto be different from the aft radial height 630, and in the example shownthe forward radial height 620 is smaller than the aft radial height 630.Further, the radial height 614 (and/or radial position) of the forwardgroove 612 may be different than the radial height 615 (and/or radialposition) of the aft groove 613. The radial positioning of the forwardand aft grooves may also be different.

It is to be understood that the invention is not to be limited to onlythe examples shown, and that the invention also includes embodimentswhere the aft groove has a smaller radial height than the forward radialgroove, the forward and aft radial grooves have different axial depths,the forward and aft radial grooves have different geometricalcross-sectional shapes and/or the forward and aft radial grooves havedifferent radial heights or are located at different radial heights. Itis also to be understood that the invention also includes embodimentswhere the forward sidewall has a larger radial height than the aftsidewall.

FIG. 7 illustrates a perspective view of a plurality of stator vanes 800inserted in or assembled to a ring segment 700, according to an aspectof the present invention. The ring segment 700 fits into (or assemblesto) the stator casing slot 604, and the stator vanes 800 fit into (orassemble to) a ring segment 700. The ring segments 700 may have one ormore ring segment characteristics that vary for each stage in the statorcasing 600. The ring segment characteristics include a radial height 740of a forward ring segment surface 732, a radial height 742 of an aftring segment surface 734, a radial height 744 of a forward ring segmentprojection 736, a radial height 746 of an aft ring segment projection738 or a ring segment axial length 730.

The ring segment's axial length 730 may be measured from the forwardsidewall or forward surface 732 to the aft sidewall or aft surface 734,or the axial length 730 may be measured from the end of the forwardprojection 736 to the end of the aft projection 738. According to anaspect of the present invention, this axial length 730 may be configuredso that it is different for each stage of the stator, for adjacentstages of the stator, or for nearby stages of the stator. This “single”configuration provides the advantage of eliminating the possibility of aring segment designed for a specific stage from being installed in anadjacent or nearby stage of the stator. For example, the axial length730 for a stage five ring segment may be 3 inches, and the axial lengthfor a stage six ring segment may be 2.75 inches, so it would beimpossible to insert the stage five ring segment into a stage six statorcasing slot, because the stage six stator casing slot would be toosmall.

Ring segments may also be installed backwards when the cross-sectionalprofile of the ring segment is symmetrical. When this happens, machineefficiency is reduced and damage may occur. According to another aspectof the present invention, the ring segment 700 has a generallytrapezoidal or quadrilateral cross-sectional profile. The radial height740 of the forward sidewall/surface 732 is configured to be differentthan the radial height 742 of the aft sidewall/surface 734, and theseheights may be measured from the base of the respective sidewalls orfrom the bottom surface of the ring segment. The radial height 740 isshown to be smaller than radial height 742, but it is to be understoodthat the radial height 740 could also be configured to be larger thanradial height 742.

In addition, the radial height 744 of the forward projection 736 may beconfigured to be smaller than the radial height 746 of the aftprojection 738. As one example only, the radial height 744 of theforward projection 736 may be about 0.25 inches while the radial height746 of the aft projection 738 may range between about 0.30 inches andabout 0.50 inches. The purpose of the difference in radial heights(between forward and aft projections) is to ensure that the ring segment700 is not installed backwards in the stator casing slot. Further,adjacent or nearby stages may have different radial heights for the aftprojection (and/or different radial heights for the forward projection)to further error-proof installation. Both the ring segments 700 and thestator vanes 800 may have their characteristics and asymmetricalprofiles (from an axial and/or radial/circumferential perspective)chosen so that both articles may only be installed (or assembled) in asingle direction, or a single configuration. This asymmetrical profileaspect will prevent backwards installation of the ring segment 700 orstator vane 800. An asymmetrical profile example is the forward surfaceof the stator vane being lower (or higher) than the aft surface, as thisrequires the stator vane to be installed in only one direction. Anotherexample is that the forward and aft projections (or grooves) havedifferent radial heights and/or positions, and this also ensures thatthe stator components are installed in a single configuration.

FIG. 8 illustrates a cross-sectional view of a stator vane 800,according to an aspect of the present invention. The stator vane 800 maybe configured to fit directly or assemble into a stator casing slot orinto a ring segment, where the ring segment is configured to engage astator casing slot. The stator vane 800 has an angled platform 810 thattapers up from a forward side 801 to an aft side 802. However, theplatform could also be configured to taper downward from the forwardside to the aft side of the stator vane. This taper ensures that thestator vane 800 can only be inserted in the designed direction on thering segment or stator casing slot, and that backwards installation isimpossible. In order to properly match the complementary surfaces of thering segment or stator casing slot, the stator vane characteristics mustcooperate with the complementary surfaces. The stator vanecharacteristics may include a radial height 821 of a forward sidewall811, a radial height 822 of an aft sidewall 812 or an axial length 850.The forward surface or forward sidewall 811 is configured to have asmaller radial height 821 than the radial height 822 of the aft surfaceor aft sidewall 812. The lower dovetail 830 or tang portion 830 isconfigured to fit within the lower portion of the ring segment slot. Theupper dovetail 840 is tapered to follow the contours of the platform 810and to allow insertion into the ring segment or stator casing slot. Theaxial length 850 of the stator vane 800 may also be configured to bedifferent for each stage or for adjacent or nearby stages to reduce oreliminate the possibility of installation in an undesired stage ringsegment or stator casing slot.

It will be apparent that the set of stator portions (e.g., ring segment700 and stator vane 800) are insertable in the stator casing slot 604.The stator casing slot 604, ring segment 700 and stator vane 800 may beconfigured so that the set of stator portions only assemble to thestator casing slot 604 in a single stage of the stator casing 600,and/or in a single configuration. For example, this arrangement preventsa stage 9 stator vane from being assembled in a stage 10 or stage 11ring segment, and also prevents a stage 7 ring segment from beingassembled in a stage 6 or stage 8 casing slot. A single configurationmay be viewed as the part for a specific stage is installed in thatstage (and not some other stage), and/or the part is installed in thecorrect orientation (i.e., not backwards from what is intended).

FIG. 9 illustrates a schematic representation of a stator, according toan aspect of the present invention. The stator 900 may be divided intomany arcuate sections or segments. An upper half 901 may include anupper half left half locker segment 911, an upper half right half lockersegment 912, and a plurality of pack segments 913-916. However, it is tobe understood that more or less pack segments could be used as desiredin the specific application. Each of the upper pack segments span anangle of θn and have a circumferential length or arc length of ARCn. θnmay be referred to as the span angle. The upper half segments may bereferred to collectively as the n-Pack.

A lower half 902 may include a lower half left half locker segment 921,a lower half right half locker segment 922, and a plurality of packsegments 923-929. However, it is to be understood that more or less packsegments could be used as desired in the specific application, as longas there are a different number of upper and lower pack segments. Eachof the lower pack segments span an angle of Gm and have acircumferential length or arc length of ARCm. θm may be referred to asthe span angle. The lower half m-segments may be referred tocollectively as the m-Pack.

According to an aspect of the present invention, and to aid in foolproofing installation of stator components, the stator has a differentnumber of n-pack segments than m-pack segments. As shown, there arefewer n-pack segments than m-pack, but this could be reversed to havemore m-pack segments than n-pack segments as desired in the specificapplication. The angle of θn is also configured to be different than theangle θm, and in the example shown θn is greater than θm. However, it isto be understood that in some applications it may be desirable to haveθm be greater than θn. The difference in angles also leads to adifference in segment arc length, as the arc length ARCn is greater thanthe arc length ARCm. However, it is to be understood that in someapplications it may be desirable to have ARCm be greater than ARCn.

According to an aspect of the present invention, an article ofmanufacture configured for use with a turbomachine has a stator 900having an upper half 901 and a lower half 902. The upper half 901 hasone or more upper half locker segments 911, 912 and a plurality of upperhalf pack segments 913-916. The upper half pack segments 913-916 arelocated circumferentially between the one or more upper half lockersegments 911, 912. The lower half 902 has one or more lower half lockersegments 921, 922 and a plurality of lower half pack segments 923-929.The lower half pack segments 923-929 are located circumferentiallybetween the lower half locker segments 921, 922. At least onecharacteristic of the upper half 901 is different than at least onecharacteristic of the lower half 902. The characteristics of both theupper half 901 and lower half 902 are chosen from one, all or a portionof, the number of pack segments, the pack segment span angle θn or θm,and pack segment arc length ARCn or ARCm.

The various features of the stator, according to an aspect of thepresent invention, are used to fool proof installation of statorcomponents. It can be seen that by physically changing the statorsegments so that the number of n-pack segments are different from thenumber of m-pack segments, configuring the angle θn to be different fromthe angle θm and by configuring the arc length ARCn to be different thanthe arc length ARCm, that it is now extremely difficult, if notimpossible, to improperly install the stator components.

Aspects of the present invention provide, an article of manufacturecomprising a first component (e.g., stator vane 800) configured for usewith a stator of a turbomachine. The first component (e.g., stator vane800) is configured for attachment to a second component (e.g., ringsegment 700) also configured for use with the stator of theturbomachine. The first component (e.g., stator vane 800) is configuredto substantially reduce the possibility of installation in an undesiredstage of the stator by modification of at least one characteristic ofthe first component. The second component (e.g., ring segment 700) isconfigured to substantially reduce the possibility of installation in anundesired stage of the stator by modification of at least onecharacteristic of the second component.

The characteristic of the stator vane 800 may be chosen from one, all,or a portion of, the radial height 821 of a forward sidewall 811, theradial height 822 of an aft sidewall 812, and an axial length 850. Thecharacteristic of the ring segment 700 may be chosen from one, all, or aportion of, the radial height 740 of a forward surface 732, the radialheight 742 of an aft surface 734, the radial height 744 of a forwardprojection 736, the radial height 746 of an aft projection 738, and anaxial length 730.

The article of manufacture may also include a third component (e.g.,stator casing slot 604) configured for use with the stator of theturbomachine. The third component is also configured for attachment tothe second component (e.g., ring segment 700). The third component(e.g., stator casing slot 604) is configured to substantially reduce thepossibility of installation in an undesired stage of the stator bymodification of at least one characteristic of the third component. Thecharacteristic of the stator casing slot 604 may be chosen from one,all, or a portion of, the radial height 620 of a forward sidewall 606, aradial height 630 of an aft sidewall 607, a radial height of a forwardgroove 612, a radial height of an aft groove 613, and an axial length605 or 610. The article(s) of manufacture, as herein described may alsobe referred to as a compressor stator assembly. The compressor statorassembly may include, some or all of, the stator casing 600, statorcasing slots 604, ring segments 700 and stator vanes 800.

FIG. 10 is a flowchart of a method 1000 for insuring proper installationof stator portions in a compressor stator assembly, according to anaspect of the present invention. In inserting step 1010, a set of statorportions are inserted in a stator casing slot 604 or stator casing 600.The stator portions may include ring segments 700 and/or stator vanes800. The inserting step 1020 may be viewed as part of step 1010, andincludes inserting a plurality of stator vanes 800 into a ring segment700. The inserting step 1030 may also be viewed as part of step 1010,and includes inserting a plurality of ring segments 700 into a statorcasing slot 604. These steps may be repeated as often as desired, oruntil the compressor stator assembly is fully assembled. As mentionedpreviously, the stator vane characteristic and the ring segmentcharacteristic are chosen so that stator vanes 800 and the ring segments700 have asymmetrical profiles from an axial and/or radial orcircumferential perspective. The asymmetrical profiles restrict or onlyallow the stator vanes and the ring segments to be assembled in a singledirection, and this prevent backwards installation of the stator vanes800 or ring segments 700.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

1. A compressor stator assembly comprising: a stator casing having aplurality of stator casing slots, a set of stator portions beinginsertable in the stator casing slots, the stator casing and the set ofstator portions being configured such that the set of stator portionsonly assembles to the stator casing in a single stage of the statorcasing, or in a single configuration.
 2. The compressor stator assemblyof claim 1, wherein the set of stator portions includes a plurality ofstator vanes, the stator vanes having a stator vane characteristic thatvaries for each stage in the stator casing, the stator vanecharacteristic comprising at least one of, a radial height of a forwardsidewall, a radial height of an aft sidewall or an axial length.
 3. Thecompressor stator assembly of claim 2, wherein the set of statorportions includes a plurality of ring segments configured to assemble tothe stator casing slots, and the stator vanes are configured to assembleto the ring segments, the ring segments having a ring segmentcharacteristic that varies for each stage of the stator casing, the ringsegment characteristic comprising at least one of, a radial height of aforward ring segment surface, a radial height of an aft ring segmentsurface, a radial height of a forward ring segment projection, a radialheight of an aft ring segment projection or a ring segment axial length.4. The compressor stator assembly of claim 3, the stator casing slotshave a casing slot characteristic that varies for each stage in thestator casing, the casing slot characteristic comprising at least oneof, a radial height of a forward casing slot sidewall, a radial heightof an aft casing slot sidewall, a radial height of a forward casing slotgroove, a radial height of an aft casing slot groove or a casing slotaxial length.
 5. The compressor stator assembly of claim 4, wherein thestator vane characteristic and the ring segment characteristic arechosen so that the stator vanes and the ring segments have asymmetricalprofiles from an axial or radial/circumferential perspective.
 6. Thecompressor stator assembly of claim 5, wherein the asymmetrical profilesonly allow the stator vanes and the ring segments to be assembled in asingle direction.
 7. The compressor stator assembly of claim 4, furthercomprising: an upper half and a lower half; the upper half having one ormore upper half locker segments and a plurality of upper half packsegments, the plurality of upper half pack segments locatedcircumferentially between the one or more upper half locker segments;the lower half having one or more lower half locker segments and aplurality of lower half pack segments, the plurality of lower half packsegments located circumferentially between the one or more lower halflocker segments; and wherein at least one characteristic of the upperhalf is different than at least one characteristic of the lower half,and the at least one characteristic of both the upper half and the lowerhalf are chosen from at least one of, a number of pack segments, a packsegment span angle, and a pack segment arc length.
 8. A compressorstator assembly comprising: an upper half and a lower half; the upperhalf having one or more upper half locker segments and a plurality ofupper half pack segments, the plurality of upper half pack segmentslocated circumferentially between the one or more upper half lockersegments; the lower half having one or more lower half locker segmentsand a plurality of lower half pack segments, the plurality of lower halfpack segments located circumferentially between the one or more lowerhalf locker segments, wherein at least one characteristic of the upperhalf is different than at least one characteristic of the lower half,and the at least one characteristic of both the upper half and the lowerhalf are chosen from at least one of, a number of pack segments, a packsegment span angle, and a pack segment arc length; each of the upperhalf and the lower half having a stator casing having a plurality ofstator casing slots; and a set of stator portions being insertable inthe stator casing slots, the stator casing and the set of statorportions being configured such that the set of stator portions onlyassembles to the stator casing in a single stage of the stator casing,or in a single configuration.
 9. The compressor stator assembly of claim8, wherein the set of stator portions includes a plurality of statorvanes, the stator vanes having a stator vane characteristic that variesfor each stage in the stator casing, the stator vane characteristiccomprising at least one of, a radial height of a forward sidewall, aradial height of an aft sidewall or an axial length.
 10. The compressorstator assembly of claim 9, wherein the stator vane characteristic ischosen so that the stator vanes have asymmetrical profiles from an axialor radial/circumferential perspective.
 11. The compressor statorassembly of claim 10, wherein the asymmetrical profiles only allow thestator vanes to be assembled in a single direction.
 12. The compressorstator assembly of claim 8, wherein the set of stator portions includesa plurality of ring segments configured to assemble to the stator casingslots, and a plurality of stator vanes are configured to assemble to thering segments, the ring segments having a ring segment characteristicthat varies for each stage of the stator casing, the ring segmentcharacteristic comprising at least one of, a radial height of a forwardring segment surface, a radial height of an aft ring segment surface, aradial height of a forward ring segment projection, a radial height ofan aft ring segment projection or a ring segment axial length.
 13. Thecompressor stator assembly of claim 12, wherein the ring segmentcharacteristic is chosen so that the ring segments have asymmetricalprofiles from an axial or radial/circumferential perspective.
 14. Thecompressor stator assembly of claim 13, wherein the asymmetricalprofiles only allow the ring segments to be assembled in a singledirection.
 15. The compressor stator assembly of claim 8, the statorcasing slots having a casing slot characteristic that varies for eachstage in the stator casing, the casing slot characteristic comprising atleast one of, a radial height of a forward casing slot sidewall, aradial height of an aft casing slot sidewall, a radial height of aforward casing slot groove, a radial height of an aft casing slot grooveor a casing slot axial length.
 16. A method of insuring properinstallation of stator portions in a compressor stator assembly, themethod comprising: inserting a set of stator portions into a statorcasing slot of a stator casing; and the stator portions being configuredsuch that each of the stator portions only assembles to the compressorstator assembly in a single configuration or in a single stage of thestator casing.
 17. The method of claim 16, the inserting a set of statorportions step further comprising: inserting a plurality of stator vanesinto a ring segment; and wherein the stator vanes have a stator vanecharacteristic that varies for each stage in the stator casing, thestator vane characteristic comprising at least one of, a radial heightof a forward sidewall, a radial height of an aft sidewall or an axiallength.
 18. The method of claim 17, the inserting a set of statorportions step further comprising: inserting a plurality of ring segmentsinto the stator casing slot; and wherein the ring segments have a ringsegment characteristic that varies for each stage of the stator casing,the ring segment characteristic comprising at least one of, a radialheight of a forward ring segment surface, a radial height of an aft ringsegment surface, a radial height of a forward ring segment projection, aradial height of an aft ring segment projection or a ring segment axiallength.
 19. The method of claim 18, wherein the stator casing slots havea casing slot characteristic that varies for each stage in the statorcasing, the casing slot characteristic comprising at least one of, aradial height of a forward casing slot sidewall, a radial height of anaft casing slot sidewall, a radial height of a forward casing slotgroove, a radial height of an aft casing slot groove or a casing slotaxial length.
 20. The method of claim 19, wherein the stator vanecharacteristic and the ring segment characteristic are chosen so thatstator vanes and the ring segments have asymmetrical profiles from anaxial or radial/circumferential perspective; and wherein theasymmetrical profiles only allow the stator vanes and the ring segmentsto be assembled in a single direction.